Radio-controlled-clock (RCC) devices that rely on time signal broadcasts have become widely used in recent years. A radio-controlled-clock (RCC) is a timekeeping device that provides the user with accurate timing information that is derived from a received signal, which is broadcast from a central location, to allow multiple users to be aligned or synchronized in time. Colloquially, these are often referred to as “atomic clocks” due to the nature of the source used to derive the timing at the broadcasting side. In the United States, the National Institute of Standards and Technology (NIST) provides such broadcast in the form of a low-frequency (60 kHz) digitally-modulated signal that is transmitted at high power from radio station WWVB in Fort Collins, Colo. The information encoded in this broadcast includes the official time of the United States. This also includes information regarding the timing of the implementation of daylight saving time (DST), which has changed in the United States over the years due to various considerations.
Reception challenges created the need for a new broadcast format, or communications protocol, for time signal broadcasts, that would allow for robust reception in various types of applications under various reception conditions while also being cost-effective. The new broadcast format, operating in accordance with the present invention, preserves the amplitude modulation and pulse-width modulation properties of the legacy time-code broadcast. This backward-compatibility property ensures that the operation of legacy devices, is not unaffected by the additional features offered by the enhanced broadcast format.